[PATCH net-next v2 11/14] net: ipv6: addrlabel: perform strict checks also for doit handlers

[Jakub Kicinski]

Make RTM_GETADDRLABEL's doit handler use strict checks when
NETLINK_F_STRICT_CHK is set.

Signed-off-by: Jakub Kicinski <jakub.kicin...@netronome.com>
---
 net/ipv6/addrlabel.c | 47 ++++++++++++++++++++++++++++++++++++++++++--
 1 file changed, 45 insertions(+), 2 deletions(-)

diff --git a/net/ipv6/addrlabel.c b/net/ipv6/addrlabel.c
index 0d1ee82ee55b..d43d076c98f5 100644
--- a/net/ipv6/addrlabel.c
+++ b/net/ipv6/addrlabel.c
@@ -523,6 +523,50 @@ static inline int ip6addrlbl_msgsize(void)
                + nla_total_size(4);    /* IFAL_LABEL */
 }
 
+static int ip6addrlbl_valid_get_req(struct sk_buff *skb,
+                                   const struct nlmsghdr *nlh,
+                                   struct nlattr **tb,
+                                   struct netlink_ext_ack *extack)
+{
+       struct ifaddrlblmsg *ifal;
+       int i, err;
+
+       if (nlh->nlmsg_len < nlmsg_msg_size(sizeof(*ifal))) {
+               NL_SET_ERR_MSG_MOD(extack, "Invalid header for addrlabel get 
request");
+               return -EINVAL;
+       }
+
+       if (!netlink_strict_get_check(skb))
+               return nlmsg_parse(nlh, sizeof(*ifal), tb, IFAL_MAX,
+                                  ifal_policy, extack);
+
+       ifal = nlmsg_data(nlh);
+       if (ifal->__ifal_reserved || ifal->ifal_flags || ifal->ifal_seq) {
+               NL_SET_ERR_MSG_MOD(extack, "Invalid values in header for 
addrlabel get request");
+               return -EINVAL;
+       }
+
+       err = nlmsg_parse_strict(nlh, sizeof(*ifal), tb, IFAL_MAX,
+                                ifal_policy, extack);
+       if (err)
+               return err;
+
+       for (i = 0; i <= IFAL_MAX; i++) {
+               if (!tb[i])
+                       continue;
+
+               switch (i) {
+               case IFAL_ADDRESS:
+                       break;
+               default:
+                       NL_SET_ERR_MSG_MOD(extack, "Unsupported attribute in 
addrlabel get request");
+                       return -EINVAL;
+               }
+       }
+
+       return 0;
+}
+
 static int ip6addrlbl_get(struct sk_buff *in_skb, struct nlmsghdr *nlh,
                          struct netlink_ext_ack *extack)
 {
@@ -535,8 +579,7 @@ static int ip6addrlbl_get(struct sk_buff *in_skb, struct 
nlmsghdr *nlh,
        struct ip6addrlbl_entry *p;
        struct sk_buff *skb;
 
-       err = nlmsg_parse(nlh, sizeof(*ifal), tb, IFAL_MAX, ifal_policy,
-                         extack);
+       err = ip6addrlbl_valid_get_req(in_skb, nlh, tb, extack);
        if (err < 0)
                return err;
 
-- 
2.19.2